Auxiliary door lock



4, 1969 HOFFMAN ET AL 3,421,787

AUXILIARY DOOR LOCK Filed June 1, 1967 I Sheet 0f 2 IN VENTORS LOUISHOFFMAN flfiTHl/I? Beak/WM! wrap/m 'Jan. 14, 1969 L. HOFFMAN ET AL3,421,787

AUXILIARY DOOR LOCK Sheet Filed June 1, 1967 INVENTORJ HOFFMAN UnitedStates Patent 4 Claims ABSTRACT OF THE DISCLOSURE Auxiliary door locksof removable or semi-permanent type, suited for use on hotel and motelroom doors and elsewhere, auxiliary to or in substitution of existingdoor locks.

Background of the invention Field of the invention.--This invention hastwo principal uses: The first is the provision of a portable, removabledoor lock which may be installed on hotel and motel room doors and thelike, to guard against unauthorized entry by persons having keys to theexisting door locks. The second use involves the provision of asemipermanent auxiliary door lock which may be mounted on door posts tosupplement existing door locks. The latter use would be applicable tomore permanent tenants, rooming house guests and apartment house andprivate home occupants. In either case the lock proper is entirelyremovable from the door when not in use.

Description of the prior art.The following United States patents weredeveloped in the course of two Patent Ofiice searches and they arebelieved to constitute the closest art to this invention: 584,677,588,619, 614,052, 692,083, 826,538, 1,252,003, 1,869,689, 1,947,773,2,067,779, 2,665,935, 2,903,286.

Summary of the invention The invention comprises three basic components:a keeper plate 'which is either removably secured or otherwise afiixedto the door post, a locking plate which engages the door, and a slidingbolt mounted on the locking plate for engagement with the keeper plate.An important feature of the invention resides in the fact that thelocking plate is caused to interlock with the keeper plate when the boltis moved into locking position. Consequently there is a locking actionby both the locking plate and the bolt with respect to the keeper plate.

Two embodiments of the invention are illustrated in the drawing anddescribed in the specification. In the first embodiment the keeper plateis provided with a hookshaped inner end portion which engages theexisting door jamb locking plate on the door post. The former is simplyhooked into the latter and is readily removable therefrom. In the secondembodiment the keeper plate is screwed or otherwise secured to the doorpost, this being in addition to the usual door jamb locking plateexisting thereon. In this second embodiment of the invention, the keeperplate is intended for relatively permanent attachment to the door postin the sense that it is not designed for removal following each use.

Brief description of the drawing FIGURE 1 is a perspective view of anauxiliary door lock made in accordance with one form of the invention,wherein the keeper plate is hooked into the existing door jamb lockingplate on the door post.

FIGURE 2 is a perspective View of the keeper plate component.

FIGURE 3 is a perspective view of the locking plate component of saiddoor lock.

3,421,787 Patented Jan. 14, 1969 "ice FIGURE 4 is a transverse sectionon the line 44 of FIGURE 3.

FIGURE 5 is a horizontal section through the assembled door lock,showing it mounted in engagement with a conventional door and door post.

FIGURE 6 is a perspective view of a conventional door and door post,showing mounted thereon a door lock made in accordance with the secondform of this invention.

FIGURE 7 is a fragmentary section taken on the line 77 of FIGURE 6.

FIGURE 8 is a fragmentary horizontal section showing how the keeperplate is secured to the door post and showing also how the locking plateengages the keeper plate.

FIGURE 9 is a perspective view of the assembled door lock made inaccordance with the second embodiment of this invention.

Description of a preferred embodiment Referring in the first instance tothe first form of this invention as illustrated in FIGURES 1-5 inclusiveit will be observed that auxiliary door lock 10 consists of three maincomponents: a keeper plate 12, a locking plate 14 and a sliding bolt 16.

The keeper plate 12 comprises an elongated strip hav ing a hook-shapedelement 20 at one end, a slightly curved or bent end portion 22 at itsopposite end, and an elongated shank 24 intermediate said hook and endportions 20 and 22, said shank being provided with a plurality of spacednotches 26 on opposite side edges thereof. A plurality of holes 28 mayalso be formed in said shank.

The locking plate 1 4 is a generally rectangular member having atransverse slot 30 formed therein to receive the keeper plate. A channel32 is formed on said locking plate between a flange 34 along one sideedge of said plate and a rib 36 formed a space-d distance from saidflange, in parallel relation thereto. Channel 3 2 is adapted to receiveand retain the sliding bolt 16 above mentioned.

The sliding bolt is a generally L-shaped member having a foot portion 40and a transversely bent handle portion 42. The foot portion is adaptedto slide within and along channel 32, handle portion 42 being theelement by which it is manually moved in either direction along saidchannel.

It will now be observed that a longitudinally extending slot 44 isformed in the foot portion of said L-shaped sliding bolt 16 and a rivet46' secured to the locking plate 14 and extending through slot 44 lockssaid sliding bolt in said channel while permitting it limitedlongitudinal movement therein.

In the use of this device hook-shaped element 20 of .keeper plate 12 ishooked into the existing locking plate 50 in door jamb 52. The lockingplate 14 is then threaded upon the shank of said keeper plate as shownin FIGURES 1 and 5. When the locking plate is relatively tight againstthe door jamb 52 and door 54 sliding bolt 16 is moved into engagementwith the nearest notch 26. However, in order to enable the sliding boltto enter said notch it is necessary to move the keeper plate laterallyso that the oppositely situated notch will engage the locking plate 14in the manner shown in FIGURE 1. Stated differently, oppositely situatednotches 26 on the keeper plate are respectively engaged by the slidingbolt and the locking plate 14. The keeper plate is accordingly notperpendicular to the plane of the locking plate. This firmly locks thetwo plates together and prevents unauthorized opening of the door,regardless of whether the existing door lock is or is not in lockingposition.

When it is desired to open the door the sliding bolt is disengaged fromthe keeper plate and this enables the keeper plate to be disengaged fromthe locking plate 14. The locking plate 14 is then removed from thekeeper Description of a second embodiment Referring now to the secondform of this invention as illustrated in FIGURES 6-9 inclusive it willbe observed that auxiliary door lock 100 consists of three maincomponents: a keeper plate 112., a locking plate 114 and a sliding bolt116.

The keeper plate 112 comprises an elongated strip having a mountingplate element 120 at one end, a rounded end portion 122 at its oppositeend and an elongated shank 124 intermediate said mounting plate and endportions 120 and 122, said shank being provided with a plurality ofspaced notches 126 on opposite side edges thereof. A plurality of holesmay optionally be formed in said shank.

The locking plate 114 is similar to that in the first form of thisinvention as above described, being a generally rectangular memberhaving a transverse slot 130 formed therein to receive the keeper plate.A channel 132 is formed on said keeper plate between a flange 134 alongone side edge of said plate and a rib 36 formed a spaced distance fromsaid flange, in parallel relation thereto. Channel 132 is adapted toreceive and retain sliding bolt 116 above mentioned.

The sliding bolt is a generally L-shaped member having a foot portion140 and a transversely bent handle portion 142. The foot portion isadapted to slide within and along channel 132, handle portion 142 beingthe element by which it is manually moved in either direction along saidchannel.

It will again be observed that a longitudinally extending slot 144 isformed in the foot portion of said L-shaped sliding bolt 116 and a rivet146 secured to the locking plate 114 and extending through slot 144locks said sliding bolt in said channel while permitting it limitedlongitudinal movement therein. It is apparent that the sliding bolt andrivet of this second embodiment are similar to the same members in thefirst embodiment.

In the use of this device mounting plate element 120 of keeper plate 112is secured by conventional permanent means to door jamb 152, as by thewood screws shown in the drawing. The locking plate 114 is then threadedupon the shank of said keeper plate as shown in FIGURES 6-9 inclusive.When the locking plate is relatively tight against the door jamb 152 andthe door 154 sliding bolt 116 is moved into engagement with the nearestnotch 126. However, in order to enable the sliding bolt to enter saidnotch it is necessary to move the locking plate rotationally so that theoppositely situated notch will engage the looking plate in the mannershown in FIGURE 7. Stated differently, oppositely situated notches 126on the keeper plate are respectively engaged by the sliding bolt and thelocking plate 114. The keeper plate is accordingly not perpendicular tothe plan of the locking plate. This firmly locks the two plates togetherand prevents unauthorized opening of the door, regardless of whether theexisting door lock is or is not in locking position.

When it is desired to open the door the sliding bolt is disengaged fromthe keeper plate and this enables the keeper plate to be disengaged fromthe locking plate 114. The locking plate 114 is then removed from thekeeper plate and the door is opened. The keeper plate remains secured tothe door jamb for repetitive use.

While there have been described two embodiments of the present inventionit is clear that other embodiments and modifications may be had inaccordance with the teachings thereof and the scope of the claims. Forexample, the holes which may be placed in the shank portions of thekeeper plate are adapted to receive a sliding cylinder bolt which may bein addition to or in place of the sliding bolt shown in the drawing andabove described. Also, the slightly curved end portion 22 of keeperplate 12 of the first form of this invention may be replaced by anyother handle means which permits manual retention of the keeper plate inthe door jamb locking plate while the door is being closed and while thesliding bolt and locking plate are being engaged therewith.

What is claimed is:

1. An auxiliary door lock comprising:

a keeper plate, said keeper plate engaging the door jamb and having aplurality of spaced notches on opposite side edges thereof;

a locking plate, said locking plate being adapted i conjunction withsaid keeper plate to constrain the door against opening; and

a sliding bolt, said sliding bolt being mounted in side- 'by-siderelationship on said locking plate and selectively engaging one of saidnotches on said keeper plate, the respective notch on the opposite edgeof said keeper plate engaging said locking plate in nonperpendicularrelation to the plane of said locking plate.

2. An auxiliary door lock in accordance with claim 1 wherein saidsliding bolt is secured in sliding relation to said locking plate bymeans of a rivet secured to said locking plate and a transverse slot insaid sliding bolt engaging said rivet.

3. An auxiliary door lock in accordance with claim 2 wherein said keeperplate comprises:

a hook-shaped end, said hook-shaped end being adapted to engage the doorjamb locking plate;

a curved opposite end; and

an elongated shank intermediate said hook-shaped end and said curvedopposite end and having said notches situated on opposite side edgesthereof.

4. An auxiliary door lock in accordance with claim 2 wherein said keeperplate comprises:

a mounting plate end, said mounting plate end being conventionallysecurable to the door jamb;

a rounded opposite end; and

an elongated shank intermediate said mounting plate end and said roundedopposite end and having said notches situated on opposite side edgesthereof.

References Cited UNITED STATES PATENTS 584,677 6/ 1897 Doyle 2922921,869,689 8/ 1932 Holland 292-288 2,903,286 9/1959 Richard 292295FOREIGN PATENTS 77,031 1/ 1954 Denmark.

MARVIN A. CHAMPION, Primary Examiner.

E. J. MCCARTHY, Assistant Examiner.

